4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> commit eaa358c7790338d83bb6a31258bdc077de120414 upstream. Mention that ->complete() should never be called from within usb_ep_queue(). Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/gadget/udc/core.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -248,6 +248,9 @@ EXPORT_SYMBOL_GPL(usb_ep_free_request); * arranges to poll once per interval, and the gadget driver usually will * have queued some data to transfer at that time. * + * Note that @req's ->complete() callback must never be called from + * within usb_ep_queue() as that can create deadlock situations. + * * Returns zero, or a negative error code. Endpoints that are not enabled * report errors; errors will also be * reported when the usb peripheral is disconnected.